In the OSTI Collections: Rare Earth Elements

Dr. Watson computer sleuthing scientist.

Article Acknowledgement:

Dr. William N. Watson, Physicist

DOE Office of Scientific and Technical Information


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Figure 1
Figure 1.  The thick border in the periodic table above marks off the chemically similar “rare earth elements” scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.  (Based on “32-column periodic table-a.png”[Wikimedia] in Wikimedia Commons, licensed under the Creative Commons Attribution-Share Alike 4.0 International license.  Original file is altered by adding the thick border around the place of the rare earth elements; accordingly this figure is also published under the same license.) 


The “rare earth elements” are not rare.  What is rare are the “earths”, or metal oxides, that these metallic elements were first discovered in.  The elements themselves can actually be found in many minerals, though in most of them the elements’ concentrations are too low for economical extraction.[Scientific American]  Rare earth elements are used in many modern products because their functions depend on those elements’ chemical and physical properties.[Wikipedia]  Several research projects sponsored by the U.S. Department of Energy explore these properties and new uses for them.  Additional research addresses the problem of obtaining the elements economically enough to meet increasing demand; some of this research examines new ways to recycle rare earth elements for reuse, while other investigations examine possible substitutes for rare earth elements to perform some functions. 


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Electromagnetic properties

How easily materials conduct electric charge is affected in part by the strength and direction of external magnetic fields applied to the space they occupy.  Some materials consist of alternating layers of a rare earth element and another “transition element” (one of the elements listed among groups 3-12 of the periodic table).  The conductivity of such a material is affected because the externally applied field influences the magnetic orientation of the material’s individual atoms, but the atoms themselves also influence the orientations of each other’s magnetic fields.  Atoms of the same element within the bulk of each layer affect each other in one way, but atoms of different elements near the interfaces between layers affect each other differently.  The material’s temperature has its own effect:  atoms in a warmer material have more agitated vibrations.  All these influences affect the overall magnetization of each layer in the material. 

An international group of researchers, some of whom were at Stanford University and the associated SLAC National Accelerator Laboratory, measured these magnetizations under varied conditions in three very simple alternating-layer materials, each with one layer of the rare earth element gadolinium sandwiched between two layers of nickel, each sandwich having a thickness of about 10 nanometers[Wikipedia].  The researchers also compared the magnetizations with a mathematical model of the influences governing those magnetizations.  When significant differences appear between measurements and what a mathematical model predicts they will be, it indicates that the model doesn’t account properly for something important.  In this case, though, the researchers’ model matched their experimental findings quite closely, even for the fairly complicated responses of the material whose inner layer of gadolinium took up the smallest fraction of its sandwich.  The Scientific Reports paper “Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni”[DoE PAGES] describes their work in detail. 

Figure 2
Figure 2.  How the magnetizations M in a 14-nanometer nickel-gadolinium-nickel sandwich are affected by an outside magnetic field H at various temperatures, according to a mathematical model and as actually determined from measurements of the sandwich’s effects on differently-polarized x-rays[Wikipedia].  Experimental measurements and mathematical model are compared for nickel (Ni) in part (a) of the figure, and for gadolinium (Gd) in part (c).  Part (b) of the figure shows what the mathematical model says about the magnetization direction at different depths of the sandwich in the situations indicated by the squares, triangles, and circles of the corresponding graphs of parts (a) and (c).  Note that the magnetization tends to saturate for high H, and also lags behind H—e.g., M switches from positive to negative, or vice versa, after H has already done so.  (After “Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni”[DoE PAGES], p. 4.)


Quite different materials known as rare earth perovskite[Wikipedia] nickelates can function as electrical conductors or insulators, depending on hard-to change factors like their thickness or the species of rare earth element they contain, as well as on things that can be tuned easily, like strain or the energizing of their substrate material by light.  Exactly how such changes make these materials switch from metallic to insulating behavior and back requires detailed information about how their electrons are arranged.  Researchers at Brookhaven National Laboratory have observed how a thin film of a representative rare earth nickelate, neodymium nickel oxide, interacts with x-rays, and have calculated what kind of electronic arrangement in the film would produce the interactions they observed.  Before their work, two very different sorts of electron arrangements both agreed with data that was already known; the researchers’ paper in Nature Communications, “Ground-state oxygen holes and the metal–insulator transition in the negative charge-transfer rare earth nickelates”[DoE PAGES], shows how their new observations are consistent with one type of arrangement but not the other.  

Rare earth elements are also components of many superconducting materials that, when refrigerated, don’t resist the flow of electric current—particularly the “high-temperature” superconductors[Wikipedia] that require much less refrigeration than the first superconductors discovered in 1911 and later.  One of many uses for superconductors is to make very strong, energy-efficient electromagnets, like the ones used to confine the energy-generating plasma[Wikipedia] of experimental fusion reactors.  These reactors produce energetic neutrons, so the superconductors need to function while being irradiated with them.  Neutron-irradiation tests of superconductors with different rare earth element content were reported in a Nuclear Materials and Energy paper entitled “Irradiation performance of rare earth and nanoparticle enhanced high temperature superconducting films based on YBCO”[DoE PAGES].  Coated electrically-conducting tapes, manufactured for use in high magnetic fields, were tested.  The coatings are variations on yttrium barium copper oxide (YCBO)[Wikipedia], which was the first material discovered to superconduct at the relatively high cryogenic[Wikipedia] temperature of liquid nitrogen.  One set of coatings replaces some fraction of the rare earth element yttrium with dysprosium; the other substitutes gadolinium instead, and is additionally doped with the transition metal zirconium.  These variations were of particular interest because of their potential for improved performance in magnetic fields. 

The tapes were tested to characterize their electrical properties, then irradiated at temperatures around 80 °C (353 kelvins[Wikipedia]) by doses ranging from 654 to 7,000 neutrons per square nanometer with energies above 100,000 electron-volts[Wikipedia], then tested again.  Although the unirradiated tapes might carry more current in magnetic fields without resistance than tapes with plain YBCO coatings could, the irradiation was found to reduce that amount of current to varying degrees when placed in magnetic fields of various strength and orientation.  Less reduction of the maximum supercurrent occurred in the dysprosium tapes than in the zirconium/gadolinium tapes.  Since other experiments had shown that irradiating plain YBCO-coated tapes reduced their maximum supercurrents at low doses but increased them at higher doses, the researchers suggested that doping produces defects in the unirradiated material similar to those induced by early-stage irradiation of plain YBCO. 

Figure 3 Left

Figure 3.  Left:  effects of different neutron irradiations on the maximum current that dysprosium barium copper oxide can conduct without resistance in various magnetic fields.  Below:  corresponding effects for two zirconium-doped YBCO-based superconductors with gadolinium substituted for some of the yttrium, before and after irradiation by 654 neutrons per square nanometer.  (After “Irradiation performance of rare earth and nanoparticle enhanced high temperature superconducting films based on YBCO”[DoE PAGES], pp. 253 and 254.)

Figure 3 right




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Optical properties

The ways in which a material’s electric charges can move determine how the material interacts with light; the possible motions can be significantly affected if even a fraction of the atoms are different from the rest, such as a few rare earth atoms among many atoms of other elements.  A group of researchers at Stony Brook University and Brookhaven National Laboratory had found from earlier investigations, particularly with quantum dots[OSTI] attached to carbon nanotubes[Wikipedia], that coupling different materials having “unique size and composition-dependent properties can yield products with unforeseen characteristics as compared with their individual components”.  The work they report in their paper “Probing charge transfer in a novel class of luminescent perovskite-based heterostructures composed of quantum dots bound to RE-activated CaTiO3 phosphors”[DoE PAGES], published in Nanoscale, optimized a similar material combination to produce longer-wave red light when exposed to light with wavelengths less than 460 nanometers.  These experiments involved making quantum dots of cadmium selenide, each about 30 to 40 nanometers wide, and attaching them to larger porous spheres (about 200 to 350 nanometers in diameter) of the perovskite cadmium titanium oxide that had been doped to varying degrees with the rare earth elements europium or praseodymium.  The presence of those particular dopants enabled electrons to move within these structures so they could radiate red light after absorbing light of shorter wavelengths.


Figure 4 Left A and B

Figure 4.  Left:  electron microscope image (A) of a cadmium selenide (CdSe) quantum dot on a praseodymium-doped sphere of calcium titanium oxide (CaTiO3), along with an electron-diffraction pattern (B) for the selected area.  Below:  dark-field electron microscope image of CdSe quantum dots anchored to praseodymium-CaTiO3 structures (A), with x-ray spectrograms highlighting the distribution of the calcium (B), titanium (C), oxygen (D), cadmium (E), and selenium (F).  (From “Probing charge transfer in a novel class of luminescent perovskite-based heterostructures composed of quantum dots bound to RE-activated CaTiO3 phosphors”[DoE PAGES], pp. 29 and 30.)

Figure 4 Below A, B, C, D, E, and F


Producing longer-wavelength, lower-frequency light by exposing its source to light with shorter wavelength and higher frequency is also characteristic of many lasers, whose output waves have the additional feature of being in step with each other.  The laser-beam source material is made of atoms that will tend to emit light once they have been energized by absorbing light of a higher frequency or by some other process.  Most of the atoms would spontaneously emit light eventually, but a few will do so very soon, and these first few photons will stimulate some of the other atoms to emit light sooner than they would otherwise—light waves that not only have the same frequency, but vibrate in step with the first few photons that stimulated their emission.  The stimulated photons in turn stimulate other atoms to do likewise, &c., producing an avalanche of photons in step with each other that constitute a laser beam.  Not every material can do this:  if too many atoms in a material spontaneously emit photons too soon, few will remain to be stimulated into emitting a photon in step with any of the others, and the spontaneously emitted photons will be an ordinary incoherent flash of light. 

Laser-beam production has one side effect:  the beam can heat up its source material while passing through it.  If the heating is too great, the material can be distorted enough to change the laser beam’s path through the material, or the material could even be fractured or chemically altered.[DTIC]  While this side effect is usually counteracted by minimizing the heating or removing the heat once it’s produced, some researchers have sought ways to keep the source material from heating up in the first place.  One possibility involves using a source material that is also fluorescent[Wikipedia], like the materials used to coat the inner surface of fluorescent light bulbs which, when exposed to light of certain frequencies, emit light of other frequencies.  Fluorescent bulb coatings emit light of visible frequencies when exposed to higher-frequency ultraviolet light, but other materials can fluoresce when exposed to light of lower frequency than the light they emit.  In the latter case, since the emitted photons have higher frequencies, they have higher energies, which they get by carrying away some of the material’s own thermal energy.  If the lower-frequency light that started the fluorescence could also energize some of the atoms to produce a laser beam of still lower frequency, the material would produce light of two frequencies—the higher frequency carrying away thermal energy, leaving the material cool enough to not distort or change while producing the lower-frequency laser beam. 

People have sought materials that would produce both beams when “pumped” by a single intermediate-frequency light source, but a different approach is described in the first part of the slide presentation “Advancing radiation balanced lasers (RBLs) in rare earth (RE)-doped solids”[SciTech Connect]:  using two light sources of different intermediate frequencies, one to induce the cooling fluorescence, the other to induce the lasing.  The author’s research group was to analyze different rare earth elements to see whether they could produce infrared laser light while fluorescing enough to avoid overheating.  Part 1 of the presentation describes their plan and displays some relevant data about these elements.  Parts 2 and 3 describe various approaches to producing the lasing material in the forms of crystals and glass fibers. 

Figure 5
Figure 5.  “Traditional” concept of radiation-balanced laser (left), which uses light of one frequency to pump (initiate) both the laser beam and the cooling fluorescence, compared with two concepts for using light of two different frequencies to pump the laser and the fluorescence.  The Type-I concept involves generating the laser and the fluorescence from electrically charged atoms (ions) of two different elements, while the Type-II would generate both from ions of a single element.  Horizontal lines represent possible energy levels of the ions that absorb or emit the light; vertical arrows represent absorbed light that “pumps” the ions by raising their energy level (green arrows) or emitted light that either constitutes the laser beam (red arrows) or removes thermal energy from the lasing material to cool it (blue arrows).  (From “Advancing radiation balanced lasers (RBLs) in rare earth (RE)-doped solids”[SciTech Connect], slide 3 of 21.)


Materials that radiate either in-step or out-of-step light waves when energized can serve as radiation detectors.  One such material, a rare earth compound whose molecules consist of one rare earth atom, two phosphate groups[Wikipedia, Wikipedia], and three atoms of an alkali metal[Wikipedia], can indicate the presence of radiation by producing flashes of light when struck by invisible higher-energy rays, whether those rays are light of much higher frequency (e.g., gamma rays[Wikipedia]) or rays of a different nature altogether (e.g., neutrons[Wikipedia]).  “Structural and Crystal Chemical Properties of Alkali Rare-earth Double Phosphates”[DoE PAGES] describes the properties of several such materials and how those properties vary according to which rare earth elements they contain, as well as methods for growing large crystals of the materials.  This data can support further investigations of the crystals’ use for detecting high-energy radiation, as well as studies of their molecular arrangements at high pressures. 


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Radiative properties

Not only can rare earth elements react to neutrons and gamma rays, their atomic nuclei can produce gamma rays.  The rate of production observed in experiments with two isotopes of the rare earth element samarium and reported in a Physical Review C paper[DoE PAGES] provides some significant information about nuclear processes.  Samarium nuclei, like those of most rare earth elements, consist of dozens of protons and neutrons, which always interact electromagnetically but undergo what are called “strong interactions”[Wikipedia] only when they’re within about a femtometer[Wikipedia] of each other.  The physical law that describes strong interactions is more complex than the law of electromagnetic interactions, and the way large numbers of protons and neutrons will be affected by those complex interactions is even more complicated.  According to calculations that aren’t obviously too inexact, energized nuclei should emit low-energy gamma rays (of around 3-4 million electron-volts or less—fairly low for a gamma ray) with a much lower intensity than one actually sees in experiments—which indicates that the calculations are failing to account for something important. 

Experiments using new detectors that could find gamma rays with energies below 1 electron-volt provided new clues about why the low-energy gamma rays are so intense in many nuclei.   Not only was this high intensity found in samarium-151 and samarium-153, but so was evidence that these nuclei also generated gamma rays of 2-3 million electron-volts because of a scissorslike motion[Wikipedia] of their proton and neutron sets—apparently making 151Sm and 153Sm the first nuclei discovered to exhibit both gamma-generating processes instead of just one or neither, thus demonstrating that the lower-energy gamma intensity is caused by something other than the “scissors” mechanism, and that the two mechanisms aren’t mutually exclusive.  The experimenters also calculated that astrophysical atom-building processes, in which samarium isotopes rapidly capture neutrons and emit gamma rays afterwards, should occur much more frequently if lower-energy gamma rays have the intensity found by experiment instead of the lack of intensity implied by early calculations. 

Beyond an atom’s nucleus, the arrangement and motions of the atom’s electrons—especially the outermost electrons—determine its chemical activity.  The outermost electrons of the rare earth elements all have very similar arrangements, which makes their chemical reactions very similar to each other.  Because of this, the rare earth elements tend to occur together in the same ore deposits; but more than that, chemical processes that are capable of separating them from each other largely depend on differences in the sizes of their atoms. 

Not only are rare earth elements chemically similar to each other, but they also have the same sort of resemblance, for the same reason, to several elements of another group:  the actinides, which are represented directly below them in the standard format of the periodic table.  This has significant consequences for the handling of nuclear reactors’ spent fuel.  Actinides and rare earth elements are both byproducts of fission reactors’ chain reactions.  When atoms of nuclear fuel are split, releasing energy, they also release neutrons.  Many of the neutrons induce other fuel nuclei to split, which keeps the chain reaction going, but some of them trigger different reactions that simply transform nuclei of one element into nuclei of another without inducing them to split.  Spent nuclear fuel will thus contain atoms of many more elements than fresh nuclear fuel does, including atoms of actinides, which can be used as nuclear fuel themselves, and of rare earth elements, which can’t. 

Because of their chemical similarity, quite special methods have to be used to separate rare earth elements from most actinides.  But the separation reactions will be interfered with if the substances needed for them tend to be changed by other reactions first—for instance, reactions induced by the radioactivity of the spent fuel.  Knowing exactly how radioactivity affects the chemicals used to separate actinides from rare earth elements can inform improvements of the separation methods.  Since alpha radiation[Wikipedia; Wikipedia] from actinides is particularly significant, a project to determine its effects was undertaken and the results reported in “Alpha Radiolysis of Nuclear Solvent Extraction Ligands Used for An(III) and Ln(III) Separations”[SciTech Connect].  The findings provide “a comprehensive understanding of the radiation chemistry of currently proposed processes” as well as “comprehensive baseline information and evaluation methods for any future proposed nuclear solvent extraction systems”, according to the report. 


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Extraction from other materials for reuse or first use

While one reason to separate rare earth elements from other material is to recover the other material for reuse, another possible purpose is to recover the rare earth elements themselves—a process that reduces the demands on mines.  Several reports deal with different methods for extracting rare earth elements for recycling.  A slide presentation “Recycling Rare Earth Elements Using Ionic Liquids: An Electrochemical Approach”[SciTech Connect] prepared by Sandia National Laboratory researchers for the Spring 2016 Meeting of the American Chemical Society describes experiments using batterylike electrochemical cells to extract erbium.  If the cell’s negative electrode[Wikipedia] contains erbium, charging up the cell removes the erbium and transports it through the cell’s conducting solution to be deposited on the positive electrode.  The slides show that different amounts of deposition were achieved with different salts, voltages, and electrode materials, though the cleanest erbium deposits were formed using the organic compound dimethylformamide[Wikipedia] rather than one of the ionic liquids, or liquid salts[Wikipedia], mentioned in the report title. 

Figure 6
Figure 6.  A voltage difference imposed on the positive electrode (anode) and negative electrode (cathode) of an electrochemical cell induces removal of erbium atoms from among others at the anode and their transport through the ionic liquid to the surface of the cathode, where they accumulate, thus allowing pure erbium to be extracted from the cell.  (From “Recycling Rare Earth Elements Using Ionic Liquids: An Electrochemical Approach”[SciTech Connect], slide 6 of 45.)


A Journal of Rare Earths paper by Oak Ridge National Laboratory researchers[DoE PAGES] describes how 60-nanometer and 500-nanometer shells of carbonized polydopamine[Wikipedia] were used to absorb rare earth atoms from solutions, especially atoms with atomic mass close to that of lanthanum.  The shells were more effective than solid carbon spheres of similar size, a result attributed to the shells’ pore structure, their total surface area per unit mass[Wikipedia], and the molecular structure of the carbonized polydopamine. 

Experiments at the National Energy Technology Laboratory (NETL) with a different organic compound, alginic acid or alginate[Wikipedia], are described in a poster[SciTech Connect] prepared for an annual section meeting of the Geological Society of America.  This material was found capable of forming a solid with 14 different rare earth elements in solutions up to acidities of pH 1.  Alginate removed different elements and concentrated them into its own structure with different efficiencies, incorporating most readily those whose atoms were smallest.  A similar selectivity for smaller rare earth atoms was exhibited by a different kind of absorber, as reported[DoE PAGES] by researchers from two other national labs, two universities, and a private company in the journal Environmental Science & Technology.  Their experiments involved bacteria (Caulobacter crescentus[Wikipedia]) that were genetically engineered so that their surfaces would display numerous tags that rare earth atoms could bind to.  The bacteria were found able to undergo repeated cycles of absorbing terbium atoms and having the atoms removed with citrate[Merriam-Webster; Wikipedia], with no loss in the bacteria’s absorptive capacity. 

Figure 7
Figure 7.  Molecular model of the axis of an alginate gel[WikipediaWikipedia] that was found able to absorb 14 different rare earth elements from solution.  The “classic ‘eggbox’ lattice structure with crosslinked polymer chains … produces the hydrogel consisting of 96 - 98% water and 2 - 4% alginate.”  (From “Studies on the use of alginate gel polymers as selective adsorbents of rare earth elements from aqueous solution” [SciTech Connect].) 

The National Energy Technology Lab poster mentioned that other research at that lab was examining the potential for extracting and recovering rare earth elements from wastes produced by coal mining and combustion.  A short technical report[SciTech Connect], and a more extensive commentary[SciTech Connect] published in the open-access journal Minerals, both mention that many other organizations have also begun such work, that NETL’s database of x-ray chemical analyses is a resource for rare earth element information related to coal and its byproducts, and that more data is needed to determine the most promising feed materials for rare earth element extraction processes. 

Results of investigations along these lines can be seen in several NETL slide presentations.  One prepared for the American Chemical Society’s Fall 2016 Meeting[SciTech Connect] shows how selected coal ashes’ rare earth element content is enriched by combining different techniques for physically separating the ashes:  by size (because smaller ash particles contain more rare earth elements), electromagnetically (because more rare earth element content is found in nonmagnetic fractions), and by density (since the higher-density fractions contain more).  The presentation also notes that rare earth elements are found in minerals that tend to contain certain elements but not others.  Another presentation to the same meeting uses coal-quality data[USGS] from the U.S. Geological Survey (USGS) to answer the question in its title, “Recovery of Rare Earth Elements from Coal and Coal Byproducts: What Have We Learned from the USGS CoalQual Database?”[SciTech Connect].  The presentation notes that the database records 136 parameters of 7,430 coal samples collected from 34 states in the 1970s and 1980s, and that 5,231 samples with rare-earth element information were selected for analysis.  Broken down by region, geologic age, and coal types, majorities of the 5,231 samples selected were from Appalachia, were formed in the Late Carboniferous (or Pennsylvanian) period[Wikipedia], and were bituminous[Wikipedia].  Rare earth elements were strongly associated with inorganic constituents.  Fewer than 10% of the samples were more than 115 to 130 parts per million rare earth elements—a rough minimum for economical extraction.  Some coal combustion byproducts were found to have higher concentrations of rare earth elements:  19 different byproducts—mostly ash samples, but including 3 coal rejects and 1 clay roof material—each had a total rare earth element content between 306 and 797 parts per million.  This was shown in an earlier NETL presentation[SciTech Connect] to the 18th International Conference on Heavy Metals in the Environment, which also described how a bright x-ray source at SLAC National Accelerator Laboratory was used to begin exploring how different rare earth elements are distributed differently in various combustion byproducts, according to the elements’ different atomic sizes and slightly different chemistry. 

Figure 8
Figure 8.  The U.S. Geological Survey’s CoalQual database records 136 parameter of 7,430 coal samples collected from 34 states in the 1970s and 1980s.  Fewer than 10% Of the 5,231 samples for which the database included information about rare-earth element content, fewer than 10% were more than 115 to 130 parts per million rare earth elements.  (From “Recovery of Rare Earth Elements from Coal and Coal Byproducts: What Have We Learned from the USGS CoalQual Database?”[SciTech Connect], slide 15 of 32.)


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Extracting rare earth elements from already-processed material—whether to use them again in something else or to make a real use of them for the first time after they’d simply provided bulk to the material—is a substitute for mining.  This kind of substitution is addressed in a pair of reports from Ames Laboratory, “International Cooperation to Development of Strategy and R&D Collaboration for Substitution of Rare Earth Resources” and “Development of Mangetocaloric Alloys without Critical Elements”, currently available from the same link[SciTech Connect] in OSTI’s SciTech Connect.  As part of a collaborative effort to use waste materials as a rare earth element source, researchers at Ames and the Korea Institute of Industrial Technology have experimented with using liquid magnesium to extract rare earth elements, particularly neodymium, from used high-strength permanent magnets.  More than 50,000 tons of such magnets are manufactured every year; among their uses are as components in wind turbines and in hybrid/electric vehicles.  Tests show that recycled materials maintain their useful properties, that lower-mass rare earth elements like neodymium and praseodymium diffuse into the liquid magnesium, and that the more massive element dysprosium remains in the magnet alloy, thus enriching the alloy’s dysprosium content. 

The Ames Lab reports go beyond finding a substitute for mining rare earth elements to also address finding substitute elements to make high-strength magnets.  Both reports describe how samples of several different alternative alloys can be produced rapidly by additive manufacturing[OSTI] to compare their performance with that of rare earth element alloys used in magnetic refrigerators[Wikipedia].  These devices avoid a significant operating cost of refrigerators based on gas compression by eliminating the compressor, but the cost savings could be offset if their magnets require expensive rare earth elements.  Various combinations of nickel, manganese, tin, copper, and cobalt were alloyed; the best candidate among these was comparable to typical magnetic-refrigeration alloys made with rare earth elements, though not to excellent ones.  This finding, however, was only a preliminary result; the researchers planned to additively manufacture many more alloys for testing. 

Another report[DoE PAGES], by researchers at Ames Laboratory, Oak Ridge National Lab, Iowa State University, and the University of Nebraska, describes investigations of alloys made from iron, cobalt, and titanium, all having the general formula Fe3+xCo3-xTi2 with x ranging from 0 to 3.  Experiments and mathematical models were used to determine the alloys’ atomic structures and how those structures relate to their magnetic properties.  Fe3+xCo3-xTi2 materials with x closer to 3—that is, with less cobalt and more iron—can attain higher magnetic fields[Wikipedia] and are harder to demagnetize[Wikipedia].  The report concludes that these properties could even be improved on by nanostructuring the materials and aligning their magnetic grains, thus making them even more useful for reducing demand for rare earth elements toward uses for which no substitutes exist. 


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Additional references

Reports available through DoE PAGES

Reports available through OSTI’s SciTech Connect


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